Implementation of Zero-Thickness Impedance Boundary Condition for Method of Moments and Application to Microstrip Antennas

To analyze a microstrip antenna consisting of a lossy metal, we proposed a scheme for a method of moments (MoM) to completely implement a zero-thickness impedance boundary condition (IBC). This model is more accurate for lossy metal than other boundary conditions, such as a resistive sheet model. The accuracy of the proposed scheme is numerically demonstrated by comparing antenna parameters, such as the scattering parameter, directivity, gain, and efficiency, computed by two commercial tools, FEKO and HFSS. These tools and the proposed scheme were applied to two microstrip antennas made from lossy metals with various conductivity.